The present invention provides a modem concentrator for use in connecting a plurality of hardwired users to a data network. The modem concentrator permits both user and network initiated connections.
As is known in communication and data network systems, users typically do not require continuous communication or data network service. Instead, users experience sporadic requirements for such services. Concentration is applied to such customers to conserve infrastructure costs of the communications or data network.
Concentration is known in the context of the public switched telephone network ("PSTN"). It involves switching telephone traffic from a large number of sources having infrequent demands for service to a smaller number of more frequently used data carriers. The data carriers typically cannot carry data from every source simultaneously.
For example, residential users of telephone service likely have encountered events where telephone calls cannot be placed because "all circuits are busy." Such events typically arise when telephone use is at its peak. This is an example of concentration. Perhaps one thousand residential customers may connect to a single central office in the PSTN. However, the central office connects to the remainder of the PSTN over lines having capacity to handle only one hundred simultaneous telephone calls. In this example, the one thousand residential telephone lines are concentrated to a data carrier having capacity for only one hundred calls. Because the residential customers' demands for service are infrequent, concentration does not degrade service significantly.
Concentration also finds application in the context of data networks, such as the Internet. In this context, customers of data network services may connect to a data network, such as the Internet, via a concentrator. The concentrator connects users at a plurality of first data ports with a data network at a plurality of second data ports. Users in this application do not move, therefore, a user may be associated with one of the data ports. The number of first data ports is greater than the number of second data ports. The users typically connect using an analog modem interface whereas the concentrator connects o the data network using a digital interface. Accordingly, the concentrator also performs a modem function. The concentrator in this context is in fact a "modem concentrator."
One such modem concentrator is disclosed in U.S. Pat. No. 5,668,857 to McHale ("McHale"). McHale discloses a communication server apparatus that establishes user initiated connections to the data network. However, it is limited because it does not establish user-network connections initiated from within the data network. Also, it cannot dynamically build an association between users and the data ports at which the users are connected to the modem concentrator.
Accordingly, there is a need in the art for a modern concentrator that establishes user-network connections initiated from within the network.